Production of artificial protein threads, fibers, filaments, and the like



Patented Aug. 18, 1953 PRODUCTION OF ARTIFICIAL PROTEIN THREADS, FIBERS, FILAMENTS, AND

THE LIKE Frank Happey, Bingley, and Robert L. Wormell, Coventry, England, assignors to Courtaulds Limited, London, England, a British company No Drawing. Application September 18, 1951, Serial No. 247,194. In Great Britain October 12,

9 Claims. 1

This invention relates to the production of artificial protein threads, fibres, filaments and the like, hereinafter generally referred to as threads, and is particularly concerned with the production of spinning solutions of keratin and regenerated keratin threads made from such solutions.

Proposals have already been made for the production of artificial threads from keratinous materials such as are present in wool waste and animal hair, horns and hooves. Such proposals usually consist in dissolving or dispersing the keratin, after suitable pretreatment, in a liquid such as cuprammonium solution, aqueous solutions of urea with or without reducing agents, or aqueous ammonia, caustic soda or sodium sulphide solution, and extruding the solution or dispersion into a coagulant bath, generally an acid bath which contains one or more salts.

It has been proposed to pretreat the keratinous material with oxidising agents. Thus, P. Alexander, R. F. Hudson and M. Fox in The Biochemical Journal, volume 46, No. 1 (1950) pages 27-32 describe pretreating keratin with oxidising agents including peracetic acid, the keratin so treated being soluble in aqueous caustic soda, ammonium hydroxide and urea solutions. It is believed that the action of peracetic acid is to oxidise and rupture the cystine link in the keratin so that the oxidised product is soluble or dispersible in alkali. The use of peracetic acid as an oxidising agent on a commercial scale, however, is undesirable; the acid itself is corrosive and unpleasant to operatives and in addition the manufacture of the acid from acetic anhydride and hydrogen peroxide is dangerous in that the reaction mixture may explode.

The bb-ject of the present invention is to provide an improved oxidative pretreatment of keratin particularly for the manufacture of regenerated keratin fibres.

According to the present invention, a process for the oxidative pretreatment of keratin comprises subjecting the keratin to the action of hydrogen peroxide in the presence of ferrous sulphate and an acid. The preferred acid is sulphuric acid but other acids such as phosphoric acid and acetic acid may also be used. The amounts of hydrated ferrous sulphate and of sulphuric acid used may be from 2 to 20 per cent by weight of the weight of keratin. It is preferred to use from 8 to 10 per cent of ferrous sulphate based on the weight of keratin. The amount of acid used should be sufficient to keep the ferrous sulphate in solution; 1 gram per litre of ferrous sulphate usually requires approximately 1 gram per litre of sulphuric acid.

The keratin pretreated according to the invention is readily soluble in dilute alkali and the present invention therefore also includes a process for the production of keratin solutions comprising subjecting the keratin to the action of hydrogen peroxide in the presence of ferrous sulphate and an acid and dissolving the oxidised keratin in an aqueous alkaline solution. The solutions obtained according to the invention may be used directly as spinning solutions in the manufacture of artificial threads; they may also be used as sizes and dispersing agents.

The invention also includes a process for the production of regenerated keratin threads comprising subjecting the keratin to the action of hydrogen peroxide in the presence of ferrous sulphate and an acid, dissolving the oxidised keratin in an aqueous alkaline solution, such as aqueous ammonia or aqueous caustic soda solution, and extruding the solution so obtained into an aqueous coagulant bath containing one or more metal salts known to coagulate proteins; suitable salts are sodium sulphate, magnesium sulphate and aluminium sulphate; mixtures of such salts may also be used. The bath preferably has a pH'value between 5.0 and 9.0.

The threads obtained according to the invention may be treated in the manner usual for artificial protein threads, including stretching, hardening, and insolubilising treatments.

The stretching of the threads may be effected by passing the thread between godets, rollers or reels the peripheral speeds of which are adjusted to give the desired amount of stretching; alternatively a pair of tapered rollers may be used. The stretching should usually be at least per cent but is preferably higher, for example from to 300 per cent. Stretching may be efiectedin air or in the presence of a coagulant bath free or substantially free from hardening agents.

The hardening baths may be any of the usual baths proposed for this purpose with casein threads, for example aqueous formaldehyde either alone or preferably in conjunction with one tract as described in United States iPatentspecification No. 2,290,789.

The regenerated keratin fibres obtained according to the invention are generally of thealpha configuration as shown by 'X-Yray analysis, and possess a wool-like elasticity.

The present invention isillustrated .by the following examples:

Example 1 The mixture was stirred for 3 hours with external cooling to keep the temperature about 20 centigrade. The mixture was then diluted with an equal volume of water and, after stirring, allowed to stand for 3 days. The solid material was separated, dissolved and extruded as described in Example 1.

The procedure described in Examples 1 and 2 ay be appliedto rabbetdownto givethreads havingv tensile properties comparable with those of the regenerated wool"products of'Ex'amples l and 2.

' What we claim is:

g A, prpgess for, the oxidative pretreatment of keratin preparatory to its solution in an aqueous alkaline solverm which comprises subjecting the keratin .to .the action of hydrogen peroxide in the presence o'fferrous sulphate and an acid chosen f rom tthegroup-cgnsisting of sulphuric acid, phosphoric acid and acetieacid.

:2."A;process for the oxidative pretreatment of 7 'keratinpreparatory to its solution in an aqueous 100 grams of wool waste were stirred'iat ZO uct was then stirred for 4 hours with 3 litres of "1.75 per centaqueous ammonium hydroxide. The liquor was filteredoff from a small insoluble residue and clarified by centrifuging in a gravitational field of ;l000. g. The clear liquor was then stirred, and sufiicient 2 N sulphuric acid added to bring the pH value to 4 so that a creamy white curd was precipitated. The curd was filtered ofi using a nainsookcloth and pressed free of extraneous liquor. The wet curd was then redissolvedby the additionof sufiicient concentrated ammonia (sp. gr. 0.88) to raise the pH value to 910.

The viscous solution obtained was then centrifuged free from air and other particles and was then extruded into an aqueous solution containing in-each litre 450 grams of crystalline magnesium sulphate (MgSO4.7I-Iz0) and 150'grams of anhydrous sodium sulphate, the pH value "of the solution being 7.0. The freshly extruded thread-was stretched 200 per centon tapered rollers with inclined axes with the lower rollers rotating in a solution having the same'composi tionas the coagulant bath. I The threads were then collected on a godet andthardened for 2 hours at 50 centrigra-de in a bath containing-in each litre 10 grams of formaldehyde, 450-grams of crystalline magnesium sulphateiand 150 grams of anhydrous-sodium sulphate and then insolubilised by further treatmentfor 2 hours in abath at 45.centrigrade containing in each litre l0 gramsof formaldehyde, 300 grams-of sodium sulphate and 100 grams of sulphuric acid. The threads were then washed in water and dried.

Example 2 alkaline solvent, which comprises subjecting the keratin to the action of hydrogen peroxide in the presence of ferrous sulphate and sulphuric acid.

3. A process for the oxidative pretreatment of keratin preparatory :to its solution in an aqueous alkaline solvent, which comprises subjecting the keratin to the action of hydrogen peroxide in the presence of from 2 to 20 per cent by weight of ferrous sulphate and from 2 to 20 per cent by weight of sulphuric acid, both percentages being based on the weight of the keratin.

4. A process for the production of keratinsolutions which comprises subjecting the keratin to the action of hydro-gen :peroxide in the presence of ferrous sulphate and-an acid chosen from the group consisting of sulphuric acid, phosphoric acid and acetic acid and dissolving theoxidised keratin inan aqueous alkaline solution.

- 5. A process .for the production of keratin solutions which comprisessubjecting the keratin to the action of hydrogen peroxide-in the presence of ferrous sulphate and sulphuric acidand dis- 7 solving the-oxidised keratinin a aqueous alkaline solution.

6. A process for the production of keratin solutions which comprises stirring together keratin and vhydrogenhperoxide in the presence of from 2 to 20 per cent by .Weightof ferrous sulphate and from 2 to 20 per cent by-weightof sulphuric acid, both percentagesbeing based on the weightof the keratin thereby oxidising the keratin, and dissolving the oxidised keratin .in an aqueous al.- kaline solution.

'7. Aprocess for the-production of regenerated keratin-threads which comprises stirring together keratin and hydrogen peroxide in the presence of ferrous sulphate and an acid chosen from the group consisting of sulphuric acid, phosphoric acid and acetic acid, thereby oxidising the keratin, dissolving the oxidisedikeratin in anaqueous ,alkaline solution and extrudingrthe solutionso obtained into anaqueous salt bath having a pH value between 5.0 and 9.0.

8. A process for the-production of regenerated keratin 'threads which comprises stirring together keratin and hydrogen peroxide in the presence of ferrous sulphate and sulphuric acid, thereby oxidising the keratin, dissolving the oxidised keratin'in an aqueous alkalinesol-ution and-extruding the solution soobt-ai-ned yintozan aqueous l thsh vineiapHwalueibetween 5.0;and 9.0..

-,:9. i l-process for: the-production of;r.egenerated k ratinathreads which .eQmprises-stirring together keratin and hydrogen peroxide in the presence of from 2 to 20 per cent by weight of ferrous sulphate and from 2 to 20 per cent by weight of sulphuric acid, both percentages being based on the weight of the keratin, thereby oxidising the keratin, dissolving the oxidised keratin in an aqueous alkaline solution and. extruding the solution so obtained into an aqueous salt bath having a pH value between 5.0 and 9.0.

FRANK HAPPEY.

R. L. WORMELL.

UNITED STATES PATENTS Name Date Schlack Sept. 2'7, 1938 OTHER REFERENCES Speakman et al., Nature, L0nc1., vol. 142, pg. 1035, 1938.

'Ser. No. 253,230, Bergh et al. (A. P. 0.), published Apr. 27, 1943.

Alexander et a1., Biochem. J., vol. 46, No. 1, pgs. 27-32, 1950.

Number 

1. A PROCESS FOR THE OXIDATIVE PRETREATMENT OF KERATIN PREPARATORY TO ITS SOLUTION IN AN AQUEOUS ALKALINE SOLVENT, WHICH COMPRISES SUBJECTING THE KERATIN TO THE ACTION OF HYDROGEN PEROXIDE IN THE PRESENCE OF FERROUS SULPHATE AND AN ACID CHOSEN FROM THE GROUP CONSISTING OF SULPHURIC ACID, PHOSPHORIC ACID AND ACETIC ACID. 